def add_two_numbers(a, b,c=10):
    return a + b

print(add_two_numbers(10,20))


def is_prime(n):
    if n <= 1:
        return False
    for i in range(2,int(n**0.5)+1):
        if n % i == 0:
            return False
    return True


print(is_prime(23))



def fibonacci(n):
    if n==0:
        return 0
    elif n==1:
        return 1
    else:
        return fibonacci(n-1)+fibonacci(n-2)
print(fibonacci(10))

def factorial(n):
    if n==0:
        return 1
    else:
        return n*factorial(n-1)
print(factorial(5))

